For students, this disruption could hardly come at a worse time - just a couple weeks before finals, and the end of the school year.

"I'm a music major here. And we got different things we have to do weekly and being out of school, a major setback on that," said Odis Rucker, sophomore.

"It's nothing to play around with. You get out of here as soon as you can. Be safe," said Brian Casson, freshman.

Administrators say a few essential staff will continue to work on campus. But as far as when everyone else can return, at this point, they're unable to say.

"We are going to rely on the advice of our law enforcement community to determine when it indeed would be safe to return to campus," said Dwyer.

The campus police chief said if closing is wrong, he wants to make sure he errs on the side of caution. Most of the students agree with him. The students are expected to be out of the campus area by noon Saturday. Some were staying Friday night. The university has offered if anybody needs help with transportation expenses to help reimburse some of them.

Officials closed down campuses in Chicago and suburban Orland Park, along with classroom space at a downtown Chicago location and canceled all classes for the liberal arts school's 5,700 students. Buildings where community events are planned will remain open, Dwyer said.

"In this day and age, given Virginia Tech and Northern Illinois University, when you have a threat made against students or other members of the university community, you have to take steps to ensure that everyone is safe," university spokesman Joe Moore said Friday. "Even if that means erring on the side of being overly cautious."

Moore declined to give more details of what the graffiti looked like.

Security has been increased on campus, including the use of Chicago police and the FBI, said Chicago police spokeswoman Monique Bond.

"We continue to monitor the situation with our federal partners and we have increased security around the area as a precaution," Bond said.

No one was in custody in connection with the threats on Friday evening.

"During this process we have relied heavily on the advice and direction of our dedicated law enforcement agencies to ensure that actions and communications regarding this matter protect the safety of all involved," Dwyer said.

Graffiti was first found April 5 in a bathroom stall at the coed dorm. The message was of a "threatening but nonspecific nature," the school said in a statement.

The incident was reported to campus authorities and Chicago police. Saint Xavier increased staff at the residence hall, which houses about 245 students, and discussed the incident with the people who lived there, officials said.

Moore said many students were interviewed and the dorm hosted group discussions to reassure students.

Then officials found the second message referencing the threat for Monday.

"Officers have conducted an aggressive investigation throughout the week," according to the university's statement. "The investigation remains open at this time."

Campuses around Illinois have been on alert since a Valentine's Day shooting when a gunman burst into a lecture hall at NIU, killing five students and wounding 18 others before turning the gun on himself.

The FBI's Joint Terrorism Task Force arrested a University of Illinois at Chicago student in late February for allegedly making e-mail threats of a "mass shooting" on the UIC campus. She was charged with one count of making threats through use of interstate commerce.

And Illinois State University said in late February police were investigating graffiti found in a dorm bathroom that referenced the NIU incident. The graffiti was scrawled in black marker on a toilet-paper dispenser and read "ISU is the next NIU."